| Clairian Ltd | Information & communication | 2020 |
| Clar Plaster and Render Limited | Construction | 2026 |
| Clara Place Investments Limited | Financial services | 2018 |
| Clarbull Ltd | Financial services | 2020 |
| Clarendon Gardens Property Management Company Limited | Households | 2017 |
| Clarendon House Properties Limited | Real estate | 1985 |
| Clarity Electrical Systems Ltd | Construction | 2018 |
| Clarity Ultrasound Limited | Health & social care | 2025 |
| Clark & Co Estates Ltd | Real estate | 2014 |
| Clark-Reid Properties Ltd | Real estate | 2025 |
| Clarks Castle Hire Ltd | Other services | 2017 |
| Clarkson Mayer Limited | Professional & scientific | 2002 |
| Class HR Ltd | Professional & scientific | 2019 |
| Class Manager Limited | Information & communication | 2018 |
| Classic Care Homes (Devon) Limited | Health & social care | 2005 |
| Classic Construction Groundwork Ltd | Construction | 2018 |
| Claudia Collaborations Ltd | Other services | 2019 |
| Clay & Rock Ltd | Wholesale & retail | 1998 |
| Clayton Property Portfolio Holdings Ltd | Real estate | 2019 |
| CLB & Associates Ltd | Public administration | 2023 |
| Clean and Bright of Devon Ltd. | Administrative & support | 2020 |
| Clean Propulsion Technologies Limited | Manufacturing | 2024 |
| Clean Slate Business Solutions Limited | Administrative & support | 2025 |
| Clean Switch Ltd | Construction | 2022 |
| Cleanerabode Limited | Administrative & support | 2017 |
| Cleanial Ltd | Administrative & support | 2024 |
| Clear Management and Distribution Consultancy Limited | Professional & scientific | 2014 |
| Clear Privacy Limited | Professional & scientific | 2024 |
| Clear Sea Cleaning Ltd | Administrative & support | 2021 |
| Clear Waste Route Ltd | Information & communication | 2026 |
| Clearfocus Training Limited | Other services | 2017 |
| Clearlight Radiology Limited | Information & communication | 2020 |
| Clearvac Group Limited | Construction | 2016 |
| Clearvac International Limited | Water & waste | 2009 |
| Clearvac Offshore Limited | Water & waste | 2021 |
| Cleve House Management Company Limited | Households | 2005 |
| Cleveland Gardens Residents Association | Households | 2006 |
| Clever Soap Limited | Wholesale & retail | 2021 |
| CLH Construction Services Ltd | Construction | 2017 |
| CLH Group Limited | Wholesale & retail | 2016 |
| Clhospitality Limited | Hospitality | 2025 |
| Clicado Media UK Limited | Professional & scientific | 2025 |
| Click 4 Business Limited | Administrative & support | 2006 |
| Click Digital Development Limited | Information & communication | 2013 |
| Clickmovements Ltd | Education | 2020 |
| Clientside F&F Ltd | Financial services | 2021 |
| Clientside Trading Limited | Construction | 2023 |
| Cliff Court (Annexe) Management Company Limited | Real estate | 1994 |
| Clifford Barton Weddings Ltd | Administrative & support | 2020 |
| Clift Farming Company | Agriculture & fishing | 1996 |
| Clift Holdings Ltd | Financial services | 2025 |
| Clifton Emery Design Limited | Professional & scientific | 2012 |
| Clifton Garage Limited | Extraterritorial | 1999 |
| Clifton Holly Legal & Advisory Limited | Professional & scientific | 2017 |
| Clifton IFA Acquisitions Ltd | Financial services | 2018 |
| Clifton Project Managements Limited | Construction | 1984 |
| Clifton Wealth Ltd | Financial services | 2010 |
| CLIMB8 Limited | Manufacturing | 2025 |
| Climbtime Limited | Administrative & support | 2000 |
| Clinton Devon Estates Limited | Extraterritorial | 2011 |
| Clinton Renewables Limited | Energy | 2014 |
| Clipper Quay (Management) Limited | Households | 1990 |
| Clockwork Accountants Limited | Professional & scientific | 2010 |
| Clockwork Accounting Services Ltd | Professional & scientific | 2009 |
| Clockwork Consultancy Ltd | Information & communication | 2020 |
| Cloud Geeni Ltd | Information & communication | 2017 |
| Clubtek Limited | Wholesale & retail | 2016 |
| Clue Crowd Limited | Financial services | 2023 |
| Clumberstone Limited | Financial services | 2016 |
| Clutch Putt Limited | Real estate | 2021 |
| Clwyd Welding Services Limited | Manufacturing | 1983 |
| Clyde House Chiropractic Clinic Ltd | Health & social care | 2014 |
| Clyst Commercials Ltd | Manufacturing | 2007 |
| Clyst Development Limited | Real estate | 2018 |
| Clyst Haven Ltd | Real estate | 2015 |
| Clyst Management Services Limited | Professional & scientific | 2006 |
| Clyst Vale Academy Trust | Education | 2011 |
| Clystcore Ltd | Professional & scientific | 2022 |
| Clystlands Management Limited | Households | 2005 |
| CM Customs Ltd | Wholesale & retail | 2023 |
| CM2 Consulting Solutions Limited | Professional & scientific | 2013 |
| Cmdelivery Ltd | Transport & logistics | 2025 |
| CMH Plumbing and Heating Ltd | Construction | 2023 |
| CMJ Property Group Ltd | Real estate | 2021 |
| CMJ SA Limited | Real estate | 2023 |
| CMP (South West) Developments Ltd | Construction | 2020 |
| CMS Supatrak Limited | Information & communication | 1993 |
| CMT Sante Limited | Health & social care | 2025 |
| CMV Property Solutions Ltd | Real estate | 2025 |
| CNC Mugalu.Healthcare Ltd | Health & social care | 2023 |
| CNC Precision Protection Ltd | Financial services | 2020 |
| Cnmluk Ltd | Transport & logistics | 2019 |
| CNR CNC Ltd | Manufacturing | 2023 |
| Co Charger Limited | Transport & logistics | 2020 |
| Co Create Exeter C.I.C. | Arts & recreation | 2021 |
| Co Create Ltd | Professional & scientific | 2017 |
| Co Create SW Ltd | Arts & recreation | 2023 |
| Coach Ella Ltd | Education | 2023 |
| Coach Therapy Ltd | Other services | 2019 |
| Coalition Promotions Limited | Wholesale & retail | 2010 |